Method for manufacturing medium-entropy alloys using additive manufacturing

Abstract

The present invention aims to provide a manufacturing method that enables the production of products of medium-entropy alloys of diverse compositions through additive manufacturing. [Solution] In order to achieve the above objective, the present invention provides a method for producing a medium-entropy alloy through additive manufacturing, wherein the additive manufacturing is performed by spraying and heating two or more alloy powders having different compositions, the alloy powders contain two or more alloying elements, and the difference in melting points between the two or more alloy powders is 400°C or less.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a medium entropy alloy through powder additive manufacturing, and particularly to a method for manufacturing a medium entropy alloy through additive manufacturing in which a plurality of alloy powders are used and the melting points between these alloy powders are 400 °C or less.

Background Art

[0002] As industrial technology has advanced, various alloys have been developed. Recently, medium entropy alloys, proposed as a new alloy system, have been developed.

[0003] High entropy alloys are alloys made by mixing five or more elements as major elements in similar proportions, different from general alloys made by adding a small amount of auxiliary elements to major elements. Even when the major elements are mixed, intermetallic compounds are not formed due to high configurational entropy, and they are alloys composed of a face-centered cubic lattice (FCC) or a body-centered cubic lattice (BCC).

[0004] Normally, alloys are classified into high entropy alloys (HEAs), medium entropy alloys (MEAs), and low entropy alloys (LEAs) according to the size of the configurational entropy (ΔS conf ) due to the composition of alloy elements, and this is classified according to the conditions of the following formula.

[0005] 〔Equation 1〕ΔS conf (LEAs) < 1.0·R 〔Equation 2〕1.0·R ≤ ΔS conf (MEAs) < 1.5·R 〔Equation 3〕1.5·R ≤ ΔS conf (HEAs) (R: Gas constant) While the development of high-entropy alloys with identical atomic composition has been active until now, recently, various medium-entropy alloys have been developed that not only possess excellent mechanical properties but can also be used in extreme environments such as cryogenic and corrosive environments, moving beyond the constraints of identical atomic composition.

[0006] Research and development are continuously being conducted to further improve desired physical properties by changing the composition, but existing casting methods have the disadvantage that screening a wide range of compositions is time-consuming and costly. [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] The present invention aims to provide a manufacturing method that enables the production of medium-entropy alloy products of diverse compositions through lamination manufacturing. [Means for solving the problem]

[0008] To achieve the above objectives, the present invention provides a method for producing a medium-entropy alloy through additive manufacturing, wherein the additive manufacturing is performed by spraying and heating two or more alloy powders having different compositions, the alloy powders contain two or more alloying elements, and the difference between the maximum and minimum melting points of each of the two or more alloy powders is 400°C or less.

[0009] Furthermore, in one embodiment of the method for producing a medium-entropy alloy according to the present invention, the difference between the maximum melting point and the minimum melting point is 120°C or less.

[0010] Furthermore, in one embodiment of the method for producing a medium-entropy alloy according to the present invention, the medium-entropy alloy may consist of 44.0 to 60.9 atomic percent of Fe, 9.3 to 24.0 atomic percent of Co, 4.3 to 23.5 atomic percent of Cr, 3.9 to 22.5 atomic percent of Ni, 0.9 to 8.4 atomic percent of Mo, and other unavoidable impurities.

[0011] Furthermore, in one embodiment of the method for producing a medium-entropy alloy according to the present invention, the two or more alloy powders include first to third alloy powders, the first alloy powder includes Fe, Co and Mo, the second alloy powder includes Fe, Cr and Ni, and the third alloy powder may include Fe, Co and Cr.

[0012] Furthermore, in one embodiment of the method for producing a medium-entropy alloy according to the present invention, the melting point of the first alloy powder is 1,400 to 1,420°C, the melting point of the second alloy powder is 1,390 to 1,410°C, and the melting point of the third alloy powder is 1,490 to 1,510°C.

[0013] Furthermore, in one embodiment of the method for producing a medium-entropy alloy according to the present invention, the heating may be performed through a laser or an electron beam. [Effects of the Invention]

[0014] The present invention provides a method for manufacturing medium-entropy alloys, enabling the efficient production of alloy products with diverse compositions. This allows for the creation of screens with various compositions during the development process, facilitating the easy production of a wide variety of products. [Brief explanation of the drawing]

[0015] [Figure 1] Figure 1 is an injection electron microscope image of an alloy powder according to one embodiment of the present invention. [Figure 2] Figure 2 is a schematic diagram illustrating a method for producing a medium-entropy alloy according to one embodiment of the present invention. [Figure 3] Figure 3 is a triangular diagram showing the composition of one embodiment of the present invention. [Figure 4] Figure 4 shows an image of an alloy product according to one embodiment of the present invention. [Figure 5] Figure 5 is a graph showing a comparison between the target composition and the actual measured composition of one embodiment of the present invention. [Figure 6] Figure 6 shows the results of X-ray diffraction analysis for an embodiment of the present invention. [Figure 7]FIG. 7 is a graph showing the hardness and crystal structure distribution by composition of an embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0016] Hereinafter, embodiments of the present application will be described in detail with reference to the attached drawings so that those having ordinary knowledge in the technical field to which the present application belongs can easily implement it. However, the present application can be embodied in various different forms and is not limited by the embodiments described herein.

[0017] Throughout the present specification, the term that a certain part "includes" a certain component means that, unless otherwise stated, it does not exclude other components but may further include other components.

[0018] Terms such as "about" and "substantially" used in this specification are used in the meaning of that numerical value or close to that numerical value when manufacturing and material tolerances inherent in the mentioned meaning are presented, and are used to prevent unscrupulous infringers from misusing the disclosed content where an exact or absolute numerical value is mentioned to assist in the understanding of the present application. Also, throughout the present specification, the phrase "the step of ~" or "the stage of ~" does not mean "the step for ~".

[0019] Throughout the present specification, the term "these combinations" included in the Markush-form expression means one or more mixtures or combinations selected from the group consisting of the components described in the Markush-form expression, and means including one or more selected from the group consisting of the said components.

[0020] Throughout the present specification, the description of "A and / or B" means "A or B, or, A and B".

[0021] The method for producing a medium-entropy alloy according to the present invention is carried out through lamination manufacturing, which is performed by spraying and heating a plurality of alloy powders having different compositions, wherein the plurality of alloy powders contain two or more alloying elements, and the difference in melting points between the two or more alloy powders is 400°C or less.

[0022] Additive manufacturing offers several advantages in metal product manufacturing, including the ability to produce complex shapes and internal structures that are impossible with existing manufacturing methods, suitability for high-mix low-volume production, and the ability to quickly create and verify prototypes.

[0023] For the additive manufacturing of metal products, powder bed fusion (PBL) manufacturing, which involves the injection and heating of metal powder, is the primary manufacturing method. The metal powder is partially melted during heating, leading to bonding. This heating is primarily achieved using concentrated energy sources such as lasers or electron beams. Representative PBL manufacturing methods include Powder Bed Fusion (PBF) and Directed Energy Deposition (DED), with PBF being the more common approach.

[0024] However, while it is not difficult to produce single-composition metal products using these layered metal powder manufacturing methods, the process of creating metal products made from alloys of various elements presents a problem: the difference in melting points between the metal elements prevents a uniform composition, leading to the formation of many defects. Conventionally, layered manufacturing was performed by combining single-element metal powders to adjust the alloy composition. As a result, even with the same energy irradiation, some powders melt while others do not, preventing a uniform composition from being ensured throughout the product.

[0025] This problem becomes even more severe when using metal powders with high melting points, such as high-entropy or medium-entropy alloys. For example, the melting point of Fe, the main element of iron-based medium-entropy alloys, is 1,538°C, while the melting points of other main elements, Cr and Mo, are 1,907°C and 2,623°C, respectively, showing a very large difference in melting points. If these elemental powders are simply mixed and manufactured in layers, the Fe powder will melt and flow excessively, while Cr, Mo, etc., will not melt, resulting in an uneven composition and creating many defects.

[0026] Another method involves first casting with the target alloy composition, then creating a powder and proceeding with printing using a single-composition alloy powder. However, in this case, it becomes difficult to produce products with diverse compositions. Once an alloy powder is created, it must be produced in large quantities, and if an alloy product is made using only one alloy powder produced through this process, it becomes impossible to introduce variations in composition.

[0027] To solve these problems, the present invention utilizes multiple alloy powders and induces the melting points of these alloy powders to be in a similar range, thereby maintaining a uniform composition in additive manufacturing. Through this, various elements with large differences in melting points can be uniformly melted. The fact that the melting point difference between the alloy powders is 400°C or less means that the difference between the highest and lowest melting points among the alloy powders is 400°C or less. Such a melting point difference is preferably 400°C or less, more preferably 200°C or less, and even more preferably 120°C or less.

[0028] This method is very advantageous for medium-entropy alloys containing metallic elements with high melting points, and through this method, medium-entropy alloys containing Fe, Co, Cr, Ni, Mo, and other unavoidable impurities can be produced.

[0029] Such medium-entropy alloys possess excellent mechanical properties and can be used even in cryogenic and corrosive environments. In particular, iron-based medium-entropy alloys, when using Cr, Mo, etc. with high melting points, benefit from the lamination manufacturing method according to the present invention, which makes the melting points of the raw material powders uniform for lamination manufacturing.

[0030] Entropy alloys with such compositions may consist, in particular, of 44-60.9 atomic% Fe, 9.3-24 atomic% Co, 4.3-23.5 atomic% Cr, 3.9-22.5 atomic% Ni, 0.9-8.4 atomic% Mo, and other unavoidable impurities. By optimizing the composition of Fe, Co, Cr, Ni, and Mo through the lamination manufacturing method according to the present invention, it is possible to achieve excellent mechanical properties as well as high corrosion resistance.

[0031] For such alloy powders with uniform melting points, the additive manufacturing method according to the present invention may be characterized in that the alloy powder comprises first to third alloy powders, the first alloy powder comprising Fe, Co, and Mo, the second alloy powder comprising Fe, Cr, and Ni, and the third alloy powder comprising Fe, Co, and Cr. Through these combinations, the difference in melting points between the alloy powders can be adjusted to 400°C or less.

[0032] In particular, the melting point of the first alloy powder containing Fe, Co, and Mo is 1,400 to 1,420°C, the melting point of the second alloy powder containing Fe, Cr, and Ni is 1,390 to 1,410°C, and the melting point of the third alloy powder containing Fe, Co, and Cr may be 1,490 to 1,510°C.

[0033] Thus, the hardness of the medium-entropy alloy produced by the present invention through other lamination methods is 170-410H on the Vickers hardness scale. v It can be characterized as being this way.

[0034] The following describes examples of medium-entropy alloys produced by the additive manufacturing method according to the present invention.

[0035] <Examples> In this invention, instead of using elemental powders, three different alloy powders containing major elements were used to ensure proper alloying, taking into account the difference in melting points.

[0036] 1st powder: Fe-Co-Mo, 2nd powder: Fe-Cr-Ni, 3rd powder: Fe-Co-Cr Referring to Figure 1, which shows the shape and atomic composition of the powders used, the process was repeated to prevent clogging of the nozzle unit into which each powder is ejected during the lamination manufacturing process. Cross-validation was then performed through particle size analysis to ensure that the proportion of fine powders was small. Table 1 below shows the composition range of the three types of powders in atomic percent.

[0037] [Table 1]

[0038] Referring to Figure 2, Figure 2 is a diagram illustrating the process of in-situ alloying, in which three types of powders are supplied together, and a laser is focused at that location to perform alloying.

[0039] During 3D printing, the supply amounts of each powder were based on weight: 20-80% for the first powder, 10-60% for the second powder, and 10-50% for the third powder.

[0040] Each of the 27 three-dimensionally shaped coupons was layered, and the amount of powder injected from each nozzle unit was changed each time the layering progressed, so that each of the 27 coupons would have a different composition.

[0041] Since the supply amount of each powder changed, the amount sprayed from each nozzle unit was altered each time the layering progressed.

[0042] The composition ratio of the powder supplied to each of the 27 coupons is shown in Figure 3.

[0043] Moving away from the existing method of first casting the alloy, then creating a powder, and then using that powder for printing, this new method combines three types of powders containing the main elements according to the desired alloy composition, allowing for the production of alloy products across a wide range of compositions.

[0044] In the case of the element Fe, the composition range was defined considering that when the amount exceeds 62.0 atomic%, the stability of the FCC phase decreases excessively, resulting in a significant decrease in flexibility, and when it is less than 44.0 atomic%, the stability of the FCC phase is excessively high, leading to a simplification of the deformation mechanism.

[0045] In the case of the Co element, the composition range was defined considering that when the amount exceeds 26.0 atomic%, the stability of the FCC phase is excessively reduced, resulting in a significant decrease in flexibility, and when it is less than 9.0 atomic%, the strength is inhibited due to a decrease in lattice strain.

[0046] In the case of Cr, the compositional range was defined considering that when the amount exceeds 24.0 atomic%, a precipitate phase that induces brittleness is formed, significantly reducing softness, and when it is less than 4.0 atomic%, the strength is inhibited due to a decrease in lattice strain.

[0047] In the case of the element Ni, the composition range was defined considering that when the Ni content exceeds 24.0 atomic%, the stability of the FCC phase is excessively high, leading to a simplification of the deformation mechanism, and when it is less than 3.5 atomic%, the stability of the FCC phase is excessively reduced, resulting in a significant decrease in flexibility.

[0048] In the case of the element Mo, the compositional range was defined considering that when the amount exceeds 8.5 atomic%, excessive precipitation is induced, significantly reducing softness, and when it is less than 0.5 atomic%, the strength is inhibited due to a decrease in lattice strain.

[0049] After manufacturing the alloy powder, in the additive manufacturing stage, the alloy powder produced in the powder manufacturing stage was ejected, and at the same time, a laser was focused to melt the powder and proceed with alloying. The printing conditions were an argon atmosphere, a powder supply rate of 3.0 g per minute, a laser output intensity of 225 W, a scan speed of 750 mm per minute, and a method that minimizes thermal history by rotating each layer at an angle of 67 degrees and proceeding with the layering in a zigzag pattern. 27 coupons of a size of 6 mm in width and height, stacked in 15 layers, were manufactured.

[0050] Finally, in the physical property evaluation stage, the properties of the 27 coupons manufactured in the aforementioned lamination manufacturing stage were evaluated. For characterization, the microstructure was analyzed through X-ray diffraction experiments and the Vickers hardness was measured.

[0051] <Example 1> Coupons were manufactured through in-situ alloying by adjusting the supply amounts of the first powder, second powder, and third powder in proportions of 80%, 10%, and 10%, respectively.

[0052] The target composition before printing was set to Fe: 61.4 atomic%, Co: 22.8 atomic%, Cr: 4.3 atomic%, Ni: 3.6 atomic%, and Mo: 7.9 atomic%.

[0053] The actual coupon composition after printing was Fe: 60.9 atomic%, Co: 22.5 atomic%, Cr: 4.3 atomic%, Ni: 3.9 atomic%, and Mo: 8.4 atomic%.

[0054] The difference between the target composition and the actual composition was Fe: 0.5 atomic%, Co: 0.3 atomic%, Cr: 0 atomic%, Ni: 0.3 atomic%, and Mo: 0.5 atomic%, indicating that the in-situ alloying proceeded with virtually no error.

[0055] <Example 2> Coupons were manufactured through in-situ alloying by adjusting the supply amounts of the first powder, second powder, and third powder in proportions of 70%, 20%, and 10%, respectively.

[0056] The target composition before printing was set to Fe: 58.1 atomic%, Co: 20.2 atomic%, Cr: 7.8 atomic%, Ni: 7.1 atomic%, and Mo: 6.8 atomic%.

[0057] The actual coupon composition after printing was Fe: 57.2 atomic%, Co: 19.4 atomic%, Cr: 8.0 atomic%, Ni: 7.8 atomic%, and Mo: 7.6 atomic%.

[0058] The difference between the target composition and the actual composition was Fe: 0.9 atomic%, Co: 0.8 atomic%, Cr: 0.2 atomic%, Ni: 0.7 atomic%, and Mo: 0.8 atomic%, indicating that the in-situ alloying proceeded with virtually no error.

[0059] <Example 3> Coupons were manufactured through in-situ alloying by adjusting the supply amounts of the first powder, second powder, and third powder in proportions of 70%, 10%, and 20%, respectively.

[0060] The target composition before printing was set to Fe: 61.1 atomic%, Co: 23.5 atomic%, Cr: 5.1 atomic%, Ni: 3.6 atomic%, and Mo: 6.8 atomic%.

[0061] The actual coupon composition after printing was Fe: 60.2 atomic%, Co: 22.6 atomic%, Cr: 5.1 atomic%, Ni: 4.3 atomic%, and Mo: 7.7 atomic%.

[0062] The difference between the target composition and the actual composition was Fe: 0.9 atomic%, Co: 0.9 atomic%, Cr: 0 atomic%, Ni: 0.7 atomic%, and Mo: 0.9 atomic%, indicating that the in-situ alloying proceeded with virtually no error.

[0063] <Example 4> Coupons were manufactured through in-situ alloying by adjusting the supply amounts of the first powder, second powder, and third powder in proportions of 60%, 30%, and 10%, respectively.

[0064] The target composition before printing was set to Fe: 54.8 atomic%, Co: 17.6 atomic%, Cr: 11.2 atomic%, Ni: 10.6 atomic%, and Mo: 5.8 atomic%.

[0065] The actual coupon composition after printing was Fe: 53.9 atomic%, Co: 16.8 atomic%, Cr: 11.7 atomic%, Ni: 11.5 atomic%, and Mo: 6.0 atomic%.

[0066] The difference between the target composition and the actual composition was Fe: 0.9 atomic%, Co: 0.8 atomic%, Cr: 0.5 atomic%, Ni: 0.9 atomic%, and Mo: 0.2 atomic%, indicating that the in-situ alloying proceeded with virtually no error.

[0067] <Example 5> Coupons were manufactured through in-situ alloying by adjusting the supply amounts of the first powder, second powder, and third powder in proportions of 60%, 20%, and 20% respectively.

[0068] The target composition before printing was set to Fe: 57.7 atomic%, Co: 20.9 atomic%, Cr: 8.5 atomic%, Ni: 7.1 atomic%, and Mo: 5.8 atomic%.

[0069] The actual coupon composition after printing was Fe: 56.7 atomic%, Co: 19.8 atomic%, Cr: 9.0 atomic%, Ni: 8.3 atomic%, and Mo: 6.2 atomic%.

[0070] The difference between the target composition and the actual composition was Fe: 1.0 atomic%, Co: 1.1 atomic%, Cr: 0.5 atomic%, Ni: 0.8 atomic%, and Mo: 0.4 atomic%, indicating that the in-situ alloying proceeded with virtually no error.

[0071] <Example 6> Coupons were manufactured through in-situ alloying by adjusting the supply amounts of the first powder, second powder, and third powder in proportions of 60%, 10%, and 30%, respectively.

[0072] The target composition before printing was set to Fe: 60.7 atomic%, Co: 24.2 atomic%, Cr: 5.8 atomic%, Ni: 3.5 atomic%, and Mo: 5.8 atomic%.

[0073] The actual coupon composition after printing was Fe: 59.7 atomic%, Co: 22.8 atomic%, Cr: 6.1 atomic%, Ni: 4.8 atomic%, and Mo: 6.6 atomic%.

[0074] The difference between the target composition and the actual composition was Fe: 1.0 atomic%, Co: 1.4 atomic%, Cr: 0.3 atomic%, Ni: 1.3 atomic%, and Mo: 0.8 atomic%, indicating that the in-situ alloying proceeded with virtually no error.

[0075] <Example 7> Coupons were manufactured through in-situ alloying by adjusting the supply amounts of the first powder, second powder, and third powder in proportions of 50%, 40%, and 10%, respectively.

[0076] The target composition before printing was set to Fe: 51.6 atomic%, Co: 15.1 atomic%, Cr: 14.5 atomic%, Ni: 14.0 atomic%, and Mo: 4.8 atomic%.

[0077] The actual coupon composition after printing was Fe: 52.9 atomic%, Co: 16.1 atomic%, Cr: 12.8 atomic%, Ni: 12.5 atomic%, and Mo: 5.6 atomic%.

[0078] The difference between the target composition and the actual composition was Fe: 1.3 atomic%, Co: 1.0 atomic%, Cr: 1.7 atomic%, Ni: 1.5 atomic%, and Mo: 0.8 atomic%, indicating that the in-situ alloying proceeded with virtually no error.

[0079] <Example 8> Coupons were manufactured through in-situ alloying by adjusting the supply amounts of the first powder, second powder, and third powder in proportions of 50%, 30%, and 20%, respectively.

[0080] The target composition before printing was set to Fe: 54.5 atomic%, Co: 18.3 atomic%, Cr: 11.9 atomic%, Ni: 10.5 atomic%, and Mo: 4.8 atomic%.

[0081] The actual coupon composition after printing was Fe: 53.2 atomic%, Co: 16.7 atomic%, Cr: 12.7 atomic%, Ni: 12.2 atomic%, and Mo: 5.1 atomic%.

[0082] The difference between the target composition and the actual composition was Fe: 1.3 atomic%, Co: 1.6 atomic%, Cr: 0.8 atomic%, Ni: 1.7 atomic%, and Mo: 0.3 atomic%, indicating that the in-situ alloying proceeded with virtually no error.

[0083] <Example 9> Coupons were manufactured through in-situ alloying by adjusting the supply amounts of the first powder, second powder, and third powder in proportions of 50%, 20%, and 30%, respectively.

[0084] The target composition before printing was set to Fe: 57.4 atomic%, Co: 21.6 atomic%, Cr: 9.2 atomic%, Ni: 7.0 atomic%, and Mo: 4.8 atomic%.

[0085] The actual coupon composition after printing was Fe: 56.6 atomic%, Co: 20.5 atomic%, Cr: 9.4 atomic%, Ni: 8.1 atomic%, and Mo: 5.4 atomic%.

[0086] The difference between the target composition and the actual composition was Fe: 0.8 atomic%, Co: 1.1 atomic%, Cr: 0.2 atomic%, Ni: 1.1 atomic%, and Mo: 0.6 atomic%, indicating that the in-situ alloying proceeded with virtually no error.

[0087] <Example 10> Coupons were manufactured through in-situ alloying by adjusting the supply amounts of the first powder, second powder, and third powder in proportions of 50%, 10%, and 40%, respectively.

[0088] The target composition before printing was set to Fe: 60.3 atomic%, Co: 24.9 atomic%, Cr: 6.5 atomic%, Ni: 3.5 atomic%, and Mo: 4.8 atomic%.

[0089] The actual coupon composition after printing was Fe: 58.9 atomic%, Co: 22.9 atomic%, Cr: 7.3 atomic%, Ni: 5.4 atomic%, and Mo: 5.5 atomic%.

[0090] The difference between the target composition and the actual composition was Fe: 1.4 atomic%, Co: 2.0 atomic%, Cr: 0.8 atomic%, Ni: 1.9 atomic%, and Mo: 0.7 atomic%, indicating that the in-situ alloying proceeded with virtually no error.

[0091] <Example 11> Coupons were manufactured through in-situ alloying by adjusting the supply amounts of the first powder, second powder, and third powder in proportions of 40%, 50%, and 10%, respectively.

[0092] The target composition before printing was set to Fe: 48.4 atomic%, Co: 12.6 atomic%, Cr: 17.8 atomic%, Ni: 17.4 atomic%, and Mo: 3.8 atomic%.

[0093] The actual coupon composition after printing was Fe: 48.4 atomic%, Co: 12.5 atomic%, Cr: 17.6 atomic%, Ni: 17.5 atomic%, and Mo: 4.0 atomic%.

[0094] The difference between the target composition and the actual composition was Fe: 0 atoms, Co: 0.1 atoms, Cr: 0.2 atoms, Ni: 0.1 atoms, and Mo: 0.2 atoms, which was almost no error, and in-situ alloying proceeded.

[0095] <Example 12> Coupons were manufactured through in-situ alloying by adjusting the supply amounts of the first powder, second powder, and third powder in proportions of 40%, 40%, and 20%, respectively.

[0096] The target composition before printing was set to Fe: 51.3 atomic%, Co: 15.8 atomic%, Cr: 15.2 atomic%, Ni: 13.9 atomic%, and Mo: 3.8 atomic%.

[0097] The actual coupon composition after printing was Fe: 50.2 atomic%, Co: 14.3 atomic%, Cr: 15.8 atomic%, Ni: 15.4 atomic%, and Mo: 4.2 atomic%.

[0098] The difference between the target composition and the actual composition was Fe: 1.1 atomic%, Co: 1.5 atomic%, Cr: 0.6 atomic%, Ni: 1.5 atomic%, and Mo: 0.4 atomic%, indicating that the in-situ alloying proceeded with virtually no error.

[0099] <Example 13> Coupons were manufactured through in-situ alloying by adjusting the supply amounts of the first powder, second powder, and third powder in proportions of 40%, 30%, and 30%, respectively.

[0100] The target composition before printing was set to Fe: 54.1 atomic%, Co: 19.0 atomic%, Cr: 12.6 atomic%, Ni: 10.5 atomic%, and Mo: 3.8 atomic%.

[0101] The actual coupon composition after printing was Fe: 52.4 atomic%, Co: 17.3 atomic%, Cr: 13.9 atomic%, Ni: 12.6 atomic%, and Mo: 3.9 atomic%.

[0102] The difference between the target composition and the actual composition was Fe: 1.7 atomic%, Co: 1.7 atomic%, Cr: 1.3 atomic%, Ni: 2.1 atomic%, and Mo: 0.1 atomic%, indicating that the in-situ alloying proceeded with virtually no error.

[0103] <Example 14> Coupons were manufactured through in-situ alloying by adjusting the supply amounts of the first powder, second powder, and third powder in proportions of 40%, 20%, and 40%, respectively.

[0104] The target composition before printing was set to Fe: 57.0 atomic%, Co: 22.3 atomic%, Cr: 9.9 atomic%, Ni: 7.0 atomic%, and Mo: 3.8 atomic%.

[0105] The actual coupon composition after printing was Fe: 54.5 atomic%, Co: 19.5 atomic%, Cr: 11.9 atomic%, Ni: 10.1 atomic%, and Mo: 4.0 atomic%.

[0106] The difference between the target composition and the actual composition was Fe: 2.5 atomic%, Co: 2.8 atomic%, Cr: 2.0 atomic%, Ni: 3.1 atomic%, and Mo: 0.2 atomic%, indicating that the in-situ alloying proceeded with virtually no error.

[0107] <Example 15> Coupons were manufactured through in-situ alloying by adjusting the supply amounts of the first powder, second powder, and third powder in proportions of 40%, 10%, and 50%, respectively.

[0108] The target composition before printing was set to Fe: 59.9 atomic%, Co: 25.5 atomic%, Cr: 7.2 atomic%, Ni: 3.5 atomic%, and Mo: 3.8 atomic%.

[0109] The actual coupon composition after printing was Fe: 58.8 atomic%, Co: 24.0 atomic%, Cr: 7.9 atomic%, Ni: 5.2 atomic%, and Mo: 4.0 atomic%.

[0110] The difference between the target composition and the actual composition was Fe: 1.1 atomic%, Co: 1.5 atomic%, Cr: 0.7 atomic%, Ni: 1.7 atomic%, and Mo: 0.2 atomic%, indicating that the in-situ alloying proceeded with virtually no error.

[0111] <Example 16> Coupons were manufactured through in-situ alloying by adjusting the supply amounts of the first powder, second powder, and third powder in proportions of 30%, 60%, and 10%, respectively.

[0112] The target composition before printing was set to Fe: 45.3 atomic%, Co: 10.1 atomic%, Cr: 21.1 atomic%, Ni: 20.7 atomic%, and Mo: 2.8 atomic%.

[0113] The actual coupon composition after printing was Fe: 44.5 atomic%, Co: 9.3 atomic%, Cr: 21.7 atomic%, Ni: 21.7 atomic%, and Mo: 2.8 atomic%.

[0114] The difference between the target composition and the actual composition was Fe: 0.8 atomic%, Co: 0.8 atomic%, Cr: 0.6 atomic%, Ni: 1.0 atomic%, and Mo: 0 atomic%, indicating that the in-situ alloying proceeded with virtually no error.

[0115] <Example 17> Coupons were manufactured through in-situ alloying by adjusting the supply amounts of the first powder, second powder, and third powder in proportions of 30%, 50%, and 20%, respectively.

[0116] The target composition before printing was set to Fe: 48.1 atomic%, Co: 13.3 atomic%, Cr: 18.5 atomic%, Ni: 17.2 atomic%, and Mo: 2.8 atomic%.

[0117] The actual coupon composition after printing was Fe: 46.7 atomic%, Co: 11.7 atomic%, Cr: 19.6 atomic%, Ni: 19.2 atomic%, and Mo: 2.9 atomic%.

[0118] The difference between the target composition and the actual composition was Fe: 1.4 atomic%, Co: 1.6 atomic%, Cr: 1.1 atomic%, Ni: 2.0 atomic%, and Mo: 0.1 atomic%, indicating that the in-situ alloying proceeded with virtually no error.

[0119] <Example 18> Coupons were manufactured through in-situ alloying by adjusting the supply amounts of the first powder, second powder, and third powder in proportions of 30%, 40%, and 30%, respectively.

[0120] The target composition before printing was set to Fe: 51.0 atomic%, Co: 16.5 atomic%, Cr: 15.8 atomic%, Ni: 13.8 atomic%, and Mo: 2.8 atomic%.

[0121] The actual coupon composition after printing was Fe: 50.7 atomic%, Co: 16.1 atomic%, Cr: 15.8 atomic%, Ni: 14.3 atomic%, and Mo: 3.0 atomic%.

[0122] The difference between the target composition and the actual composition was Fe: 0.3 atomic%, Co: 0.4 atomic%, Cr: 0 atomic%, Ni: 0.5 atomic%, and Mo: 0.2 atomic%, indicating that the in-situ alloying proceeded with virtually no error.

[0123] <Example 19> Coupons were manufactured through in-situ alloying by adjusting the supply amounts of the first powder, second powder, and third powder in proportions of 30%, 30%, and 40%, respectively.

[0124] The target composition before printing was set to Fe: 53.8 atomic%, Co: 19.7 atomic%, Cr: 13.2 atomic%, Ni: 10.4 atomic%, and Mo: 2.8 atomic%.

[0125] The actual coupon composition after printing was Fe: 50.8 atomic%, Co: 16.2 atomic%, Cr: 15.9 atomic%, Ni: 14.3 atomic%, and Mo: 2.9 atomic%.

[0126] The difference between the target composition and the actual composition was Fe: 3.0 atomic%, Co: 3.5 atomic%, Cr: 2.7 atomic%, Ni: 3.9 atomic%, and Mo: 0.1 atomic%, indicating that the in-situ alloying proceeded with virtually no error.

[0127] <Example 20> Coupons were manufactured through in-situ alloying by adjusting the supply amounts of the first powder, second powder, and third powder in proportions of 30%, 20%, and 50%, respectively.

[0128] The target composition before printing was set to Fe: 56.7 atomic%, Co: 23.0 atomic%, Cr: 10.6 atomic%, Ni: 6.9 atomic%, and Mo: 2.8 atomic%.

[0129] The actual coupon composition after printing was Fe: 53.6 atomic%, Co: 19.4 atomic%, Cr: 13.2 atomic%, Ni: 11.0 atomic%, and Mo: 2.9 atomic%.

[0130] The difference between the target composition and the actual composition was Fe: 3.1 atomic%, Co: 3.6 atomic%, Cr: 2.6 atomic%, Ni: 4.1 atomic%, and Mo: 0.1 atomic%, indicating that the in-situ alloying proceeded with virtually no error.

[0131] <Example 21> Coupons were manufactured through in-situ alloying by adjusting the supply amounts of the first powder, second powder, and third powder in proportions of 20%, 60%, and 20%, respectively.

[0132] The target composition before printing was set to Fe: 45.1 atomic%, Co: 10.9 atomic%, Cr: 21.7 atomic%, Ni: 20.5 atomic%, and Mo: 1.9 atomic%.

[0133] The actual coupon composition after printing was Fe: 44.0 atomic%, Co: 9.4 atomic%, Cr: 22.4 atomic%, Ni: 22.1 atomic%, and Mo: 2.1 atomic%.

[0134] The difference between the target composition and the actual composition was Fe: 1.1 atomic%, Co: 1.5 atomic%, Cr: 0.7 atomic%, Ni: 1.6 atomic%, and Mo: 0.2 atomic%, indicating that the in-situ alloying proceeded with virtually no error.

[0135] <Example 22> Coupons were manufactured through in-situ alloying by adjusting the supply amounts of the first powder, second powder, and third powder in proportions of 20%, 50%, and 30%, respectively.

[0136] The target composition before printing was set to Fe: 47.9 atomic%, Co: 14.1 atomic%, Cr: 19.1 atomic%, Ni: 17.1 atomic%, and Mo: 1.9 atomic%.

[0137] The actual coupon composition after printing was Fe: 46.3 atomic%, Co: 12.2 atomic%, Cr: 20.5 atomic%, Ni: 19.2 atomic%, and Mo: 1.7 atomic%.

[0138] The difference between the target composition and the actual composition was Fe: 1.6 atomic%, Co: 1.9 atomic%, Cr: 1.4 atomic%, Ni: 2.1 atomic%, and Mo: 0.2 atomic%, indicating that the in-situ alloying proceeded with virtually no error.

[0139] <Example 23> Coupons were manufactured through in-situ alloying by adjusting the supply amounts of the first powder, second powder, and third powder in proportions of 20%, 40%, and 40% respectively.

[0140] The target composition before printing was set to Fe: 50.7 atomic%, Co: 17.3 atomic%, Cr: 16.5 atomic%, Ni: 13.7 atomic%, and Mo: 1.9 atomic%.

[0141] The actual coupon composition after printing was Fe: 49.1 atomic%, Co: 15.1 atomic%, Cr: 17.8 atomic%, Ni: 16.1 atomic%, and Mo: 2.0 atomic%.

[0142] The difference between the target composition and the actual composition was Fe: 1.6 atomic%, Co: 2.2 atomic%, Cr: 1.3 atomic%, Ni: 2.4 atomic%, and Mo: 0.1 atomic%, indicating that the in-situ alloying proceeded with virtually no error.

[0143] <Example 24> Coupons were manufactured through in-situ alloying by adjusting the supply amounts of the first powder, second powder, and third powder in proportions of 20%, 30%, and 50%, respectively.

[0144] The target composition before printing was set to Fe: 53.5 atomic%, Co: 20.4 atomic%, Cr: 13.9 atomic%, Ni: 10.3 atomic%, and Mo: 1.9 atomic%.

[0145] The actual coupon composition after printing was Fe: 51.0 atomic%, Co: 17.2 atomic%, Cr: 16.0 atomic%, Ni: 13.7 atomic%, and Mo: 2.0 atomic%.

[0146] The difference between the target composition and the actual composition was Fe: 2.5 atomic%, Co: 3.2 atomic%, Cr: 2.1 atomic%, Ni: 3.4 atomic%, and Mo: 0.1 atomic%, indicating that the in-situ alloying proceeded with virtually no error.

[0147] <Example 25> Coupons were manufactured through in-situ alloying by adjusting the supply amounts of the first powder, second powder, and third powder in proportions of 10%, 60%, and 30%, respectively.

[0148] The target composition before printing was set to Fe: 44.8 atomic%, Co: 11.7 atomic%, Cr: 22.2 atomic%, Ni: 20.4 atomic%, and Mo: 0.9 atomic%.

[0149] The actual coupon composition after printing was Fe: 43.4 atomic%, Co: 9.5 atomic%, Cr: 23.5 atomic%, Ni: 22.5 atomic%, and Mo: 1.1 atomic%.

[0150] The difference between the target composition and the actual composition was Fe: 1.4 atomic%, Co: 2.2 atomic%, Cr: 1.3 atomic%, Ni: 2.1 atomic%, and Mo: 0.2 atomic%, indicating that the in-situ alloying proceeded with virtually no error.

[0151] <Example 26> Coupons were manufactured through in-situ alloying by adjusting the supply amounts of the first powder, second powder, and third powder in proportions of 10%, 50%, and 40%, respectively.

[0152] The target composition before printing was set to Fe: 47.6 atomic%, Co: 14.8 atomic%, Cr: 19.7 atomic%, Ni: 17.0 atomic%, and Mo: 0.9 atomic%.

[0153] The actual coupon composition after printing was Fe: 45.3 atomic%, Co: 11.9 atomic%, Cr: 21.8 atomic%, Ni: 20.2 atomic%, and Mo: 0.9 atomic%.

[0154] The difference between the target composition and the actual composition was Fe: 2.3 atomic%, Co: 2.9 atomic%, Cr: 2.1 atomic%, Ni: 3.2 atomic%, and Mo: 0 atomic%, indicating that the in-situ alloying proceeded with virtually no error.

[0155] <Example 27> Coupons were manufactured through in-situ alloying by adjusting the supply amounts of the first powder, second powder, and third powder in proportions of 10%, 40%, and 50%, respectively.

[0156] The target composition before printing was set to Fe: 50.4 atomic%, Co: 18.0 atomic%, Cr: 17.1 atomic%, Ni: 13.6 atomic%, and Mo: 0.9 atomic%.

[0157] The actual coupon composition after printing was Fe: 50.2 atomic%, Co: 17.1 atomic%, Cr: 17.1 atomic%, Ni: 14.5 atomic%, and Mo: 1.1 atomic%.

[0158] The difference between the target composition and the actual composition was Fe: 0.2 atomic%, Co: 0.9 atomic%, Cr: 0 atomic%, Ni: 0.9 atomic%, and Mo: 0.2 atomic%, indicating that the in-situ alloying proceeded with virtually no error.

[0159] The 27 medium-entropy alloys produced contain Fe: 44-60.9 atomic%, Co: 9.3-24 atomic%, Cr: 4.3-23.5 atomic%, Ni: 3.9-22.5 atomic%, and Mo: 0.9-8.4 atomic%.

[0160] Table 2 below shows the actual printed composition, and Figure 5 demonstrates that in-situ alloying proceeded with almost no error from the target composition.

[0161] [Table 2]

[0162] (X-ray diffraction analysis results) Figure 6 shows the results of X-ray diffraction measurements at room temperature for manufactured examples 1 through 27.

[0163] X-ray diffraction measurements were performed after polishing the specimen surface with sandpaper in the following order: 400, 600, 800, and 1200 grit, to prevent contamination of the specimen surface.

[0164] As a result, as can be seen in Figure 6, Example 1, which had the lowest Ni composition, was observed to exhibit a single-body-centered cubic structure. Ni is a well-known stabilizing element for face-centered cubic structures, and the stability of the face-centered cubic phase tends to decrease as the composition of this element decreases.

[0165] In Examples 2, 3, 5, 6, 9, 10, 14, and 15, which had relatively low Ni content, it was observed that face-centered cubic and body-centered cubic structures coexisted.

[0166] On the other hand, the remaining 18 examples were observed to exhibit a single-face-centered cubic structure.

[0167] (Analysis results of Vickers hardness) Figure 7 is a graph showing the degree of Vickers hardness for each specific hardness level.

[0168] Vickers hardness was measured by applying a force of 500 gf for 15 seconds three times, taking positional deviation into account, and then averaging the results.

[0169] As a result, as can be seen in Figure 7, it was observed that the higher the fraction of the body-centered cubic structure, the higher the hardness.

[0170] Table 3 summarizes the values ​​observed from three measurements, along with their mean and standard deviation.

[0171] [Table 3]

[0172] [Table 4]

[0173] Thus, by simply adjusting the injection amounts of multiple alloy powders through the method for producing medium-entropy alloys according to the present invention, it was possible to freely manufacture alloy products with diverse compositions and properties.

Claims

1. A method for manufacturing a medium-entropy alloy through additive manufacturing, The aforementioned additive manufacturing is carried out by spraying and heating two or more alloy powders having different compositions. A method for producing a medium-entropy alloy through lamination, characterized in that the alloy powder contains two or more alloying elements, and the difference between the maximum and minimum melting points of each of the two or more alloy powders is 400°C or less.

2. A method for producing a medium-entropy alloy by lamination manufacturing according to claim 1, characterized in that the difference between the maximum melting point and the minimum melting point is 120°C or less.

3. The method for producing a medium-entropy alloy by lamination according to claim 1, characterized in that the medium-entropy alloy consists of 44.0 to 60.9 atomic percent Fe, 9.3 to 24 atomic percent Co, 4.3 to 23.5 atomic percent Cr, 3.9 to 22.5 atomic percent Ni, 0.9 to 8.4 atomic percent Mo, and other unavoidable impurities.

4. The method for producing a medium-entropy alloy through lamination according to claim 3, characterized in that the two or more alloy powders include first to third alloy powders, the first alloy powder includes Fe, Co and Mo, the second alloy powder includes Fe, Cr and Ni, and the third alloy powder includes Fe, Co and Cr.

5. A method for producing a medium-entropy alloy by lamination according to claim 4, characterized in that the melting point of the first alloy powder is 1,400 to 1,420°C, the melting point of the second alloy powder is 1,390 to 1,410°C, and the melting point of the third alloy powder is 1,490 to 1,510°C.

6. The method for producing a medium-entropy alloy by additive manufacturing according to claim 1, characterized in that the heating is performed through a laser or an electron beam.

7. The hardness of the medium-entropy alloys produced through the aforementioned additive manufacturing process is 170 to 410 H on the Vickers hardness scale. ｖ A method for producing a medium-entropy alloy through lamination manufacturing as described in claim 1, characterized in that...

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